Online Resource 2
![Online Resource 2](http://media.springernature.com/full/springer-static/esm/art%3A10.1007%2Fs13595-017-0666-6/MediaObjects/13595_2017_666_Fig5_ESM.jpg)
Root collar diameter (RCD, mm) by measurement date for five pine seedling types grown over 13 months in greenhouse conditions. The repeated measures ANOVA for RCD was significant by time (F = 1762.8; p < 0.01), species type (F = 16.0; p < 0.01), and their interaction (F = 10.6; p < 0.01). There were significant differences in RCD between species types in August (F = 12.5; p < 0.01), January (F = 13.8; p < 0.01), and May (F = 22.8; p < 0.01). (JPEG 2486 kb)